Document Detail


Use of opposing reflex stimuli and heart rate variability to examine the effects of lipophilic and hydrophilic beta-blockers on human cardiac vagal control.
MedLine Citation:
PMID:  10545309     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Evidence from animal studies suggests that beta-blockers can act within the central nervous system to increase cardiac vagal motoneuron activity. We have attempted to determine whether such an effect is evident in healthy humans, by examining the effects of lipophilic and hydrophilic agents on heart rate variability and cardiac vagal reflexes. A total of 20 healthy volunteers took part in the study. Autonomic studies were performed after 72 h of treatment with placebo, atenolol or metoprolol in a blinded cross-over design. ECG recordings were taken at rest and during mental and orthostatic stress. Heart rate variability was measured in the time and frequency domains. The effects on heart rate of two opposing cardiac vagal reflexes were examined. Trigeminal stimulation causing vagal stimulation, and isometric forearm muscle contraction ('muscle heart reflex') causing vagal inhibition, were performed alone and simultaneously. At rest, during mental stress and during trigeminal stimulation, beta-blocker therapy was associated with significantly increased high-frequency beat-to-beat heart rate variability when compared with placebo. There were no significant differences in effects on heart rate or heart rate variability between atenolol and metoprolol. Analysis of the muscle heart reflex, alone and with simultaneous trigeminal stimulation, showed that the magnitude of the R-R interval response was significantly greater after beta-blocker therapy compared with placebo, but the effects of atenolol and metoprolol were equivalent. beta-Blocker therapy increased cardiac vagal activity, as shown by measures of high-frequency heart rate variability and reflex studies. Lipophilic and hydrophilic beta-blockers appeared to be equally efficacious in increasing the cardiac vagal modulation of heart rate.
Authors:
J C Vaile; J Fletcher; M Al-Ani; H F Ross; W A Littler; J H Coote; J N Townend
Related Documents :
8800029 - Heart rate variability during the first 24 hours of successfully reperfused acute myoca...
8868979 - Increased myocardial [123i]-metaiodobenzylguanidine uptake after enalapril treatment in...
3941369 - Iodine-131 metaiodobenzylguanidine intra- and extravesicular accumulation in the rat he...
9262329 - Sympathetic neurotransmission in isolated rat atria after sensory-motor denervation by ...
9323859 - Recognition of individual heart rate patterns with cepstral vectors.
20067509 - Autonomic alterations and cardiac changes in epilepsy.
16138949 - Role of vasopressin antagonists in the management of acute decompensated heart failure.
22106299 - The inflammasome promotes adverse cardiac remodeling following acute myocardial infarct...
18179529 - Real-time three-dimensional echocardiography permits quantification of left ventricular...
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical science (London, England : 1979)     Volume:  97     ISSN:  0143-5221     ISO Abbreviation:  Clin. Sci.     Publication Date:  1999 Nov 
Date Detail:
Created Date:  2000-01-12     Completed Date:  2000-01-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7905731     Medline TA:  Clin Sci (Lond)     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  585-93; discussion 609-10     Citation Subset:  IM; S    
Affiliation:
Departments of Cardiovascular Medicine and Physiology, University of Birmingham, Edgbaston, Birmingham B15 2TH, U.K. j.c.vaile@bham.ac.uk
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adolescent
Adrenergic beta-Antagonists / pharmacology*
Adult
Atenolol / pharmacology
Baroreflex / drug effects*,  physiology
Cross-Over Studies
Double-Blind Method
Electric Stimulation
Electrocardiography / drug effects
Heart Rate / drug effects*
Humans
Male
Metoprolol / pharmacology
Parasympathetic Nervous System / drug effects,  physiology
Trigeminal Nerve / physiology
Vagus Nerve / drug effects*,  physiology
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 29122-68-7/Atenolol; 37350-58-6/Metoprolol
Comments/Corrections
Comment In:
Clin Sci (Lond). 1999 Nov;97(5):609-10   [PMID:  10545312 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Baseline heart rate variability in healthy centenarians: differences compared with aged subjects (>7...
Next Document:  Increased intracellular calcium and decreased activities of leucocyte Na+,K+-ATPase and Ca2+-ATPase ...